FMP Initial concept and ideas
For this project I wish to create a cooperative platform that puts players in the control of a zombie’s limbs. Players have to work together to escape the graveyard where they have risen from the dead! The desired effects of the game are moments of chaos and hilarity, this would be well represented through the implementation of 3D phsyics and cooperative play.
Aims and Objectives
The FMP will put into practice the output of my Thesis, these being the Game Design Patterns for cooperative games. A consequence of this project will be to also explore cooperative gameplay and design.
- Implement GDPs from thesis – The GDPs from my thesis focus on player customization and how these choices can result in meaningful consequences that affect the game.
- Cooperative gameplay – The GDPs specifically focus on player customization in cooperative games, as such this project will also involve the implementation of a cooperative system that allows for cooperative play.
- Physics based game with Limbs – For this project I will also want to explore physics based gameplay, this would involve featuring mechanics that involve rigidbodies and forces. As well as designing obstacles that would challenge such mechanics.
Features
- 2-4 Player coop. Each player controlling one unique limb.
- Split screen output, each screen focusing on one limb.
- Physics based movement.
- Platformer style-obstacles, requiring cooperative action to overcome.
- Each limb can be customized by the controlling player.
- Customization options include abilities, length and size of hand.
- Limb choice will influence the obstacles spawned in the map.
- Graveyard keeper will be patrol the graveyard to capture the zombie.
Gamplay loop
- Players choose a limb position (Left Arm, Right Arm, Left Leg, Right Leg).
- Players choose what type of limb: Skeleton, bloated, boneless…
- Players customize limb properties: Length, Size…
- Level begins with Zombie in the coffin, all players move their limbs to bust out of the coffin.
- Players must navigate around the map and find the exit.
- Identify the obstacles blocking the exit.
- Players work cooperatively to manoeuvre the entire Zombie body towards the exit.
- Reaching the exit ends the Level.
Games to Case study
- Human: Fall Flat (2016): has limb based mechanics to manipulate the arms of the player avatar. The limbs are used to overcome physics based obstacles. This game also features a limited set of customization options for player avatar models. There is also a split-screen coop mode.
- Octodad: Dadliest Catch (2010): again the main mechanic is controlling the limbs of the avatar. The player is able to pick up and throw objects found in the environment to solve various objectives. The player must also avoid causing too much chaos in front of NPCs to keep their Octopus identity secret. There is also a multiplayer cooperative mode where players can control separate limbs.
- Tom Clancy’s Rainbow Six Siege (2015): features limited choices in customization that affects a players approach to the game in many ways.
- Screencheat (2016): has unique approach to split screen output. Where players watch other screens to acquire information on the other players location to eliminate the respective player. This approach is required as every player is invisible in Screencheat.
- WWE 2K19 (2018): In-depth limb and body customization. Allows players to create different types of wrestlers based on choices.
PREVIS
This is a previsual for what the split screen layout may look like. David had commented on how this split screen layout may compromise the player’s view of the central zombie body, this may need additional consideration.
Approach to limb movement mechanics
Cursory research into games like Human: Fall Flat and Octodad make use of ragdoll physics. In a Post-mortem for Octodad: Dadliest Catch (2015), Kevin Geisler explains that the Octodad body was:
- Composed of hard segments that was controlled by forces with no Inverse Kinematics applied.
- Smaller forces were applied to the rest of the body to keep the body stable.
- The feet were made to be extremely heavy when not in use this was done to simulate stepping.
- This was mixed with stretchable limbs to allow more freedom of movement.
- Use of XML file to handle multiple input devices to handle button mapping.
- Limb movement is done in two axis planes in relation to the camera view with two corresponding movement input buttons. For example, with a ps4 controller, a limb can be moved along the X-Y plane using one thumbstick, the other moves the stick along the Y-Z plane.
- End of arm limbs can also grab objects
Human: Fall flat makes use of an active ragdoll body that blends animations and Inverse Kinematics. This is applied to a rigged body with armatures, and joints for the different body parts. The control of the limbs is composed of the following:
- One button controls one arm, e.g left mouse button controls left arm, right mouse button controls right arm.
- Mouse buttons engage the arms, they extend outwards reaching in front of the body, should the end of the arms collide with an object it is picked up by the body. If it is a wall then the arms stick to the wall.
- Top torso’s facing direction follows camera direction. That is if the camera looks up, the top half of the body faces up, if it faces down the body bends over at the hip facing down.
What can be used:
- The limbs being composed of multiple small bodies that can be controlled by the player.
- The controls needed to mappable to multiple controller devices.
- Various small forces to stabilise the entire body.
- Grab and hold abilites for limbs.
- An active ragdoll body.
Ragdoll prototype
Working with ragdolls is fairly new to me, as such a prototype for the ragdoll had been developed. This body is able to somewhat stablilise itself with simple animation, however manipulation of the limbs resulted in disastrous results. This had been developed with the following tutorial: https://www.youtube.com/watch?v=-pX-PobRLzk&t=567s (Jasony, 2021). The issue was likely with the manipulation of the limbs, the transform of which were oddly affected by the method of rotation.
This made it clear that the easier approach would be to implement limbs separately from the body. That is the limbs should be a separate object and mesh from the body. Therefore the next step for the project would be to implement a prototype of single limbs and test different approaches on how the limbs would be controlled.
Two limb control approaches
Approach 1
Dedicated inputs for controlling the rotation of the shoulder joint, these are designed for the thumbsticks in mind.
Approach 2
Player controls the direction of the end of the limb, another input controls hand movement along this direction.
References
- Geisler, K., 2015. Octodad: Dadliest Catch Post-Mortem Pt. 4: Tech. [Blog] Octodad: Dadliest Catch Post-Mortem, Available at: <https://www.gamasutra.com/blogs/KevinGeisler/20150330/240000/Octodad_Dadliest_Catch_PostMortem_Pt_4_Tech.php> [Accessed 20 July 2021].
- Jasony (2021). How to Create Gang Beast Character in Unity (Active Ragdoll Tutorial). [Online Video]. Available at: <https://www.youtube.com/watch?v=-pX-PobRLzk&t=567s>. [Accessed 20 July 2021].
- No Brakes Games, Code Glue, d3t, Lab42, 2016. Human: Fall Flat. [Video Game] Windows, Linux, MacOS, Playstation 4, Xbox One, Nintendo Switch, Android, iOS, Xbox Series X/S, Playstation 5, Curve Digital, 505 Games.
- Samurai Punk, 2016. Screencheat. [Video Game] Microsoft Windows, Linux, OS X, Playstation 4, Xbox One, Nintendo Switch. Surprise Attack.
- Ubisoft Montreal, 2015. Tom Clancy’s Rainbow Six Siege. [Video Game] Windows, Linux, MacOS, Playstation 4, Xbox One, Nintendo Switch, Android, iOS, Xbox Series X/S, Playstation 5. Ubisoft.
- Young Horses, 2010. Octodad: Dadliest Catch. [Video Game] Android, iOS, Linux, Microsoft Windows, Nintendo Switch, OS X, Playstation 4, PlayStation Vita, tvOS, Wii U, Xbox One. Young Horses.
- Yuke’s, 2018. WWE 2K19. [Video Game] Microsoft Windows, Playstation 4, Xbox One. 2K Sports.